This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. C12 Halo beads did provide higher peak capacity with longer gradient runs;however the results were not significant, about 10% higher. With shorter gradients the Halo beads did not provide significant gains compared to the tradition 4 um C12 beads. One pitfall of the HALO beads was the high back pressure which often lead to blown fittings or pressure overloads after only a few runs